1. Field of the Invention
The present invention relates to a method and associated apparatus for detecting position, spatial orientation and/or velocity of a plurality of light occluding objects by optical means and, more specifically, is adapted to be used beneficially in respect of computer terminal display monitors.
2. Description of the Prior Art
It has been known to employ, in respect of computers, various devices in lieu of conventional keyboard input for directing attention to a particular graphic object as by pointing. For example, light pens and the so-called "mouse" have been known as means for pointing to objects on a computer video monitor. It has also been known to permit such pointing to accomplish selection of alternatives from a limited menu.
It has been known to interrupt a plurality of beams with a single object and provide an indication of that single object. See, for example, U.S. Pat. Nos. 3,673,327 and 4,517,559. It has also been known to interrupt a widely-dispersed light beam to block some subset of an array of sensors. See U.S. Pat. No. 4,247,767.
It has also been known to employ a plurality of charge-coupled-devices (CCD) to determine the position within an x-y axis arrangement of a single object. See, also, "CCDs in Optical Touch Panels Deliver High Resolution", Electronic Design Sept. 27, 1980, pp. 139-143(a) and 43(b).
In spite of these prior art disclosures, there remains a very real and substantial need for a device which is adapted to provide a precision indication of position and spatial orientation of a plurality of objects and velocity of the same.